Image forming apparatus, method of controlling the same, and storage medium

ABSTRACT

An image forming apparatus, and a method of controlling it. The apparatus performs, in a case where at least one function out of a plurality of functions of the apparatus ceases to be usable, degeneracy control for operating to provide functions other than the at least one function, and stores information indicating a degeneracy control state is entered. The apparatus controls so as to activate without initialization operation of an image forming mechanism in a case where it is determined that the activation is due to the return from a power saving mode and the information is stored and so as to activate with the initialization operation when the activation is due to a power of the apparatus being turned on.

This application is a continuation of U.S. application Ser. No.14/095,868, filed Dec. 3, 2013 (pending), the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an image forming apparatus, a method ofcontrolling the same, and a storage medium.

Description of the Related Art

There exists known degeneracy control for operating to provide only thefunctions that can be realized without using troubled parts, in a casewhere one or more parts are troubled in an image forming apparatushaving various functions such as printing, scanning, and faxing, asopposed to all of the functions of the image forming apparatus becomingunusable. Such degeneracy control is recited in Japanese PatentLaid-Open No. 2002-320066 for example. Specifically, the image formingapparatus detects troubles upon power activation of each engine (forexample a printer engine or a scanner engine), and in cases where itfurther determines that the trouble is such that the degeneracy controlis possible, it transitions to the degeneracy control. A return to anormal state from the degeneracy control is performed when power of theapparatus is once again activated after a serviceman has changed thetroubled part.

Also, in recent years, power saving in image forming apparatuses hasreceived attention and image forming apparatuses with a built-in powersaving mode that aims to improve power saving in the image formingapparatus have become commercially available. This kind of image formingapparatus power saving mode suppresses electric power consumption bystopping electric power supply to the printer engine and the scannerengine when they are not being used; electric power supply is onlyinitiated to the necessary engine unit at a timing at which the useruses the corresponding function. For example, when a print instructionis received while the image forming apparatus is in the power savingmode and power is not being supplied to the printer engine, electricpower supply to the printer engine is resumed. Here, after the printerengine is initialized (calibration), printing is executed in accordancewith the print instruction.

However, if, hypothetically, the electric power supply to the printerengine is always resumed and the printer engine is always initializedwhen the print instruction is received during the power saving mode asdescribed above, the following problem occurs. For example, even in acase where a trouble occurred in a part of the printer engine beforetransitioning to the power saving mode and the degeneracy control wasbeing performed, the electric power supply to the printer engine isresumed upon the print instruction, and printer engine initiationinitialization (calibration) is executed. Because of this there is thepossibility that the trouble in the printer engine is worsened.

SUMMARY OF THE INVENTION

An aspect of the present invention is to eliminate the above-mentionedproblems with the conventional techniques.

A feature of the present invention is to provide a technique in which aworsening of a state of trouble in an engine is prevented by notexecuting engine (image forming mechanism) initialization processing ina case where an apparatus is activated in a power saving mode in a statewhere degeneracy control is being executed.

According to an aspect of the present invention, there is provided animage forming apparatus, comprising: an image forming unit configured toform an image on a sheet; a control unit configured to control operationof the image forming unit; and a storage unit configured to storeinformation indicating that a function of the image forming unit isrestricted. The control unit: (A) does not execute an initializationoperation of the image forming unit in a case where the storage unitstores the information and the image forming apparatus activates from apower saving state in which an electric power supply to the control unitis stopped, and (B) does execute the initialization operation of theimage forming unit in a case where the storage unit does not store theinformation and the image forming apparatus activates from the powersaving state.

According to another aspect of the present invention, there is providedan image forming apparatus having an engine, an engine controller forcontrolling the engine, and a main controller capable of communicatingwith the engine controller. The main controller is configured to outputan activation instruction to the engine controller in accordance with anactivation of the image forming apparatus. The engine controllercomprises: a determination unit configured to determine, in accordancewith the activation instruction, whether or not degeneracy control wasperformed prior to the activation; a first activation unit configured todetermine, in a case where the determination unit determined thatdegeneracy control was performed, whether or not the activation is dueto a return from a power saving mode, and configured to activate,prohibiting initialization processing of the engine, in a case where theactivation is due to the return from the power saving mode; and a secondactivation unit configured to activate, executing the initializationprocessing of the engine in a case where the determination unitdetermined that the degeneracy control was not performed or in a casewhere the activation is not due to the return from the power savingmode.

According to another aspect of the present invention, there is providedan image forming apparatus having an engine, an engine controller forcontrolling the engine, and a main controller capable of communicatingwith the engine controller. The main controller comprises: adetermination unit configured to determine, in accordance with anactivation of the image forming apparatus, whether or not degeneracycontrol was performed prior to the activation; a first activation unitconfigured to activate the image forming apparatus, prohibitinginitialization processing of the engine, in a case where thedetermination unit determined the degeneracy control was performed; anda second activation unit configured to activate the engine controllerand the engine in a case where the determination unit determined thatthe degeneracy control was not performed.

According to another aspect of the present invention, there is providedan image forming apparatus having an engine, an engine controller forcontrolling the engine, and a main controller capable of communicatingwith the engine controller. The main controller comprises: a storageunit configured to store degeneracy information from the enginecontroller; a power saving unit configured to transition, in a casewhere a condition of a power saving mode is satisfied, to the powersaving mode; a control unit configured to output, to the enginecontroller, when the degeneracy information is stored in the storageunit upon transition to the power saving mode by the power saving unit,a control signal for controlling so that, upon return from the powersaving mode, initialization processing of the engine is not performed;and an activation unit configured to make an instruction so as toactivate the engine controller upon return from the power saving mode.The engine controller comprises: an activation control unit configuredto initiate an activation in accordance with the instruction of theactivation unit, and further configured to activate, prohibiting, or notprohibiting, initialization processing of the engine in accordance withthe control signal.

According to another aspect of the present invention, there is providedan image forming apparatus having a power saving mode, comprising: adegeneracy control unit configured to perform, in a case where at leastone function out of a plurality of functions of the image formingapparatus ceases to be usable, degeneracy control for operating toprovide functions of the plurality of functions other than the at leastone function; a storage unit configured to store information indicatingthat a degeneracy control state in which the degeneracy control isperformed by the degeneracy control unit is entered; a determinationunit configured to determine, when instructed of an activation of theimage forming apparatus, whether the activation is due to a return froma power saving mode or whether the activation is due to an electricpower source of the image forming apparatus being turned on; and anactivation control unit configured to control so as to activate withoutperforming an initialization operation of an image forming mechanism ina case where the determination unit determines that the activation isdue to the return from the power saving mode and the storage unit storesthe information, and so as to execute the activation along with theinitialization operation of the image forming mechanism in a case wherethe determination unit determines that the activation is due to anelectric power source of the image forming apparatus being turned on.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a view for showing a configuration of a printing system (imageforming system) according to a first embodiment of the presentinvention.

FIG. 2 is a block diagram for explaining a hardware configuration of animage forming apparatus according to the first embodiment.

FIG. 3 is a block diagram for explaining a software configuration of amain controller and an engine controller of the image forming apparatusaccording to the first embodiment.

FIG. 4 is a flowchart for describing activation processing in the maincontroller of the image forming apparatus according to the firstembodiment.

FIG. 5 is a flowchart for describing activation processing in the enginecontroller of the image forming apparatus according to the firstembodiment.

FIG. 6 is a flowchart for describing activation processing in the maincontroller of the image forming apparatus according to a secondembodiment in a case where a power is activated.

FIG. 7 is a flowchart for describing activation processing in the enginecontroller of the image forming apparatus according to the secondembodiment.

FIG. 8 is a flowchart for describing processing in the image formingapparatus according to the second embodiment in a case of returning fromthe power saving mode.

FIG. 9 is a flowchart for describing processing in the main controllerin a case where the image forming apparatus according to a thirdembodiment transitions to the power saving mode.

FIG. 10 is a flowchart for describing shutdown processing by the enginecontroller of the image forming apparatus according to the thirdembodiment.

FIG. 11 is a flowchart for describing processing in a case where themain controller of the image forming apparatus according to the thirdembodiment returns from the power saving mode.

FIG. 12 is a flowchart for describing processing in a case where theengine controller of the image forming apparatus according to the thirdembodiment returns from the power saving mode.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described hereinafter indetail, with reference to the accompanying drawings. It is to beunderstood that the following embodiments are not intended to limit thescope of the claims of the present invention, and that not all of thecombinations of the aspects that are described according to thefollowing embodiments are necessarily required with respect to the meansto solve the problems according to the present invention.

[First Embodiment]

FIG. 1 is a view for showing a configuration of a printing system (imageforming system) according to a first embodiment of the presentinvention.

Here, a host computer (information processing apparatus) 100 and animage forming apparatus (printer) 101 are connected via a network 102.In this printing system 1, the host computer 100 and the printer 101communicate bi-directionally via the network 102. Note, the network 102may be a wired network such as a LAN or USB, or may be a wirelessnetwork such as a wireless LAN.

FIG. 2 is a block diagram for explaining a hardware configuration of theimage forming apparatus 101 according to the first embodiment.

The image forming apparatus 101 comprises such things as a maincontroller 210, an engine controller 200, and a printer engine (imageforming mechanism) 240. The main controller 210 manages such things asstate transition of the image forming apparatus 101, is capable ofcommunicating with the engine controller 200 and controls operation ofthe image forming apparatus 101 on the whole. A CPU 211 executes variouscontrol processing such as reading control and transmission control inaccordance with a control program stored in a ROM 215. A RAM 212 is usedas a temporary storage area such as a main memory or a work memory ofthe CPU 211. A DISK (hard disk) 216 stores image data, various programs,and various setting information in a non-volatile manner. An externalI/F 217 is an external interface for performing communication with theengine controller 200. An electric power control unit 209 controls theturning on and off of switches 222 and 223, and controls electric powersupply to the main controller 210 and the engine controller 200. The CPU211 and above described components are connected via a bus 218 fortransferring control signals and data.

An operation unit 220 is equipped with a touch panel, has a displayunit, keys and the like, and provides an interface function to a user. ALAN I/F 221 controls an interface between the image forming apparatus101 and the network 102.

The engine controller 200 is a controller for controlling the printerengine 240. The engine controller 200 controls the printer engine 240 inaccordance with instructions from the main controller 210 and sends innotification various information of the printer engine 240 to the maincontroller 210. A CPU 201 executes various control processing such asreading control and transmission control in accordance with a controlprogram stored in a ROM 203. A RAM 202 is used as a temporary storagearea such as a main memory or a work memory or the CPU 201. An I/O 204is an input and output interface for performing communication with theprinter engine 240. An external I/F 205 is an external interface forperforming communication with the main controller 210. The CPU 201 andabove described components are connected via a bus 206 for transferringcontrol signals and data. An EEPROM 207 is used for storing such thingsas degeneracy information (explained later) in a non-volatile manner.

The printer engine 240 is a part that handles image forming of the imageforming apparatus 101 controlled by the engine controller 200, and isequipped with a photosensitive drum, a transfer drum, a fixing unit,paper feed/discharge units, and various sensors (not shown).

A power unit 230 supplies electric power to each unit in the imageforming apparatus 101. When the image forming apparatus 101 is poweredoff, an AC power supply 250 is disconnected by a power switch 251. Byturning on the power switch 251, AC power supply is supplied to theAC-DC converter 252 and DC voltage is output. Two independent types ofelectric power control are possible with instructions of the CPU 211 inthe image forming apparatus 101. Specifically, by the electric powercontrol unit 209 turning off the switch 233, an electric power supply224 to the main controller 210 can be stopped. This corresponds to acase of a sleep mode, for example. Also, by turning off the switch 222,an electric power supply 225 to the engine controller 200 and theprinter engine 240 can be stopped. In this way, by the electric powercontrol unit 209 turning on and off the switches 222 and 223, electricpower can be supplied as necessary to locations in the image formingapparatus 101 and electric power supply can be stopped.

Note, numeral 226 denotes locations to which electric power is suppliedin the sleep mode; even in sleep mode, electric power supply to theelectric power control unit 209, the RAM 212, the operation unit 220 andthe LAN I/F 221 is continued. Electric power supply to the electricpower supply locations 226 is always maintained in any power savingmode.

Below are details of each power state in the power saving mode.

(A) Sleep Mode

The sleep mode is a state in which the electric power consumption of theimage forming apparatus 101 is reduced as much as possible. Peripheraldevices of the CPU 211 are put into a general suspend state (such asACPI-S3), only the electric power supply locations 226 are powered, andelectric power consumption of the image forming apparatus 101 on thewhole can be reduced dramatically. Specifically, the CPU 211 saves astate of the image forming apparatus 101 to the DISK 216 or in backupRAM, turns off the switch 233, and stops the electric power supply tothe main controller 210 including the CPU 211. In this state, the CPU211 itself stops operating, but the electric power control unit 209 canprocess an interrupt signal due to an input from the operation unit 220or the LAN I/F 221. Then, for example, upon network reception from theLAN I/F 221 or operation on the operation unit 220, the electric powercontrol unit 209 detects the interrupt signal, the switch 233 is turnedon, and electric power supply to the main controller 210 is initiated.With this, the CPU 211 reads out the state of the image formingapparatus 101 stored in the DISK 216 or the backup RAM, performsresetting, and transitions to a standby state, having returned to thestate immediately before the power of the main controller 210 was turnedoff. In the sleep mode, because not many hardware components canoperate, the only function is to transition to the standby state. Aninput job is received, after transitioning to the standby state.

(B) Standby State

A state in which the main controller 210 is being powered. In thisstate, operation by an operator is received from the operation unit 220,and jobs, and the like, are received from the LAN I/F 221 via thenetwork 102.

When the initiation of a job is instructed, the job is executed afterthe CPU 211 initiates electric power supply to the engine controller 200by turning on the switch 222 because the engine controller 200 ispowered off. It is possible to reduce standby power consumption in thestandby state by stopping electric power supply to the engine controller200 and the printer engine 240 and only power necessary devices when thejob completes.

In the image forming apparatus 101 having the above configuration, forexample, an instruction to return from the sleep mode is input from theoperation unit 220, for example. With this, firstly, the main controller210 and the engine controller 200 execute start-up operations of suchkinds of initialization as initial setting of each of the CPUs andmemory checking.

Next, the engine controller 200 initiates control of the printer engine240 which is under its control. At this time, generally, statetransition information of the image forming apparatus 101 is detected bythe main controller 210, and based on the detected information, theengine controller 200 performs control on each driving target. The statetransition information is information indicating whether, for example,an activation is due to the power being turned on or due to returningfrom the sleep mode, and how to transition to the next state.

In contrast to this, in the image forming apparatus 101 according to thefirst embodiment, by the configuration of a function to be explainednext, the engine controller 200 initiates control of each driving targetunder its control without waiting for start-up operation of the maincontroller 210.

FIG. 3 is a block diagram for explaining a software configuration of themain controller 210 and the engine controller 200 of the image formingapparatus 101 according to the first embodiment. Note, this software isstored in the ROMs 203 and 215.

Firstly, explanation will be given for the main controller 210.

A main control section 301 of the main controller 210 performs controlof the main controller 210 on the whole, and sends instructions to anactivation control section 302 and a sleep control section 303. Theactivation control section 302 performs control of activation of themain controller 210 and the engine controller 200. In a case where amain power of the image forming apparatus 101 is turned off, theactivation control section 302 receives an instruction from the maincontrol section 301 and transmits a shutdown request to the enginecontroller 200. In a case where the main power is turned on, theactivation control section 302 receives an instruction from the maincontrol section 301 and turns on the power of the engine controller 200.The sleep control section 303 controls conditions for transition to thesleep mode, and controls whether or not to transition to the sleep mode.Conditions for transition to the sleep mode are set in the image formingapparatus 101 beforehand. In a case where the sleep control section 303determines that transition to the sleep mode is possible, it notifiesthe main control section 301 to transition to the sleep mode, andtransmits a sleep request to the engine controller 200. Also, in a caseof returning from the sleep mode, the main control section 301 makes aninstruction to the activation control section 302 to initiate electricpower supply to the engine controller 200.

Next, explanation will be given for the engine controller 200. An enginecontrol section 311 of the engine controller 200 performs control of theengine controller 200 on the whole, sends instructions to an engineactivation control section 312, and acquires degeneracy information anderror detection information from a degeneracy detection section 313 andan error detection section 314 respectively. When the sleep request issent in notification to the engine controller 200 from the maincontroller 210, the engine control section 311 outputs an instructionfor sleep processing to each controller of the engine controller 200.When the sleep processing ends, the engine controller 200 transitions tothe sleep mode. The degeneracy detection section 313 turns on, andstores, to the EEPROM 207, a degeneracy history flag in a case wheretrouble occurs in a part of the printer engine 240, for example, and aparticular function cannot be used.

FIG. 4 is a flowchart for describing activation processing in the maincontroller 210 of the image forming apparatus 101 according to the firstembodiment. Note, this processing may be realized by storing a programfor executing this processing in the ROM 215 and by the CPU 211 readingout and executing this program.

This processing is initiated with the main controller 210 activating,and firstly, in step S401, the CPU 211 activates the engine controller200 by outputting an activation instruction to the engine controlsection 311 via the external I/Fs 217 and 205. Next the processingproceeds to step S402, and the CPU 211 determines whether the activationof the engine controller 200 is an activation due to returning from thesleep mode or an activation due to the power of the image formingapparatus 101 being turned on (power switch 251 being turned on).Regarding this determination, the CPU 211, for example, stores the sleepmode in non-volatile memory, and upon being activated due to aninterrupt from the operation unit 220 or the LAN I/F 221, it isdetermined that the activation is due to a return from the sleep mode ifthe sleep mode is stored. Also, it can be determined whether or not theinterrupt is due to the power switch 251 being turned on. The result ofthis determining is sent in notification to the engine controller 200via the external I/Fs 217 and 205. Next, the processing proceeds to stepS403, and the CPU 211 turns on the switch 222 and activates byinitiating electric power supply to the engine controller 200.

FIG. 5 is a flowchart for describing activation processing in the enginecontroller 200 of the image forming apparatus 101 according to the firstembodiment. Note, this processing may be realized by storing a programfor executing this processing in the ROM 203 and by the CPU 201executing this program.

This processing is initiated upon the engine controller 200 beingactivated, and firstly, in step S501, the CPU 201 acquires thedegeneracy history flag in the EEPROM 207, and determines whether or notthe degeneracy history flag is on. Here, if the degeneracy history flagis on, because the degeneracy control state, in which a particularfunction of the printer engine 240 cannot be used is entered, theprocessing proceeds to step S502. The degeneracy control is control foroperating, in a case where at least one of the parts of the imageforming apparatus 101 has a trouble, and at least one function out of aplurality of functions of the image forming apparatus ceases to beusable, to provide functions other than those that cannot be used, i.e.to provide only functions that can be realized and to not use thetroubled part or parts. In step S502, the CPU 201 acquires from the maincontroller 210 information indicating whether the activation is due to areturn from the sleep mode or a return due to the power switch 251 beingturned on. Then, the processing proceeds to step S503, and it isdetermined whether or not the activation is due to a return from thesleep mode. If it is due to a return from the sleep mode, the processingproceeds to step S504, and the CPU 201, i.e. the engine activationcontrol section 312, activates the printer engine 240, prohibiting aninitialization operation due to calibration (a first activation), andthe processing ends.

On the other hand, when, in step S503, it is determined that theactivation is not due to a return from the sleep mode, the processingproceeds to step S505, and the CPU 201 turns off (clears) the degeneracyhistory flag in the EEPROM 207. Next, the processing proceeds to stepS506 and the CPU 201, i.e. the engine activation control section 312,makes a calibration instruction to the printer engine 240. Also, in stepS501, in a case where the degeneracy history flag is off, the processingproceeds to step S506 and the engine activation control section 312makes a calibration instruction to the printer engine 240 (a secondactivation). Next, the processing proceeds to step S507, and the CPU 201determines whether or not an error was detected by the error detectionsection 314, and when an error was detected, the processing proceeds tostep S508, but when an error was not detected, the activation processingends. In step S508, the CPU 201, i.e. the degeneracy detection section313, detects whether the error is a target of degeneracy control, and ina case where it is a target of degeneracy control, the processingproceeds to step S509, and the CPU 201 turns on the degeneracy historyflag in the EEPROM 207. Next, the processing proceeds to step S510, andthe CPU 201, i.e. the engine control section 311, transitions theprinter engine 240 to the degeneracy control. In the degeneracy control,only functions that can be executed are executed, and functions of theprinter engine 240 for which errors were detected are not used. Next,the processing proceeds to step S511, the degeneracy information is sentin notification to the main controller 210, and the processing ends.

On the other hand, in a case where, in step S508, the CPU 201 determinedthat the error could not be degeneracy controlled, the processingproceeds to step S512, and the error information detected by the CPU201, i.e. the error detection section 314, is sent in notification tothe main controller 210 via the external I/Fs 205 and 217. Here, becausethe image forming apparatus 101 cannot be used until the error iscancelled, a serviceman must be called. Next, in step S513, the CPU 201transitions to an error state in which a serviceman call is necessary,and the processing ends.

As explained above, by the first embodiment, the engine controller 200returns from the sleep mode without activating the printer engine 240 ina case of a return from the sleep mode in a degeneracy state. With this,there is an effect that damage of the printer engine due to performancecalibration of the printer engine upon activation can be prevented.Also, because there is a high possibility that the degeneracy controlwill be cancelled in a case of activation due to the power switch of theimage forming apparatus 101 being turned on, calibration of the printerengine is performed upon activation. As a result, upon return from thesleep mode, when there is no possibility that the degeneracy iscancelled, calibration of the printer engine can be restricted. Also,upon activation due to power activation for which there is a highpossibility that the degeneracy control is cancelled, calibration of theprinter engine can be performed.

[Second Embodiment]

Next, explanation will be given for the second embodiment of the presentinvention. Because the hardware configuration of the image formingapparatus 101 according to the second embodiment is the same asconfiguration in FIG. 2 according to the previously described firstembodiment, its explanation will be omitted. In the second embodiment,the main controller receives a notification of presence or absence ofdegeneracy from the engine controller, and stores the degeneracyinformation in a non-volatile manner. Next, in a case where the maincontroller checks the degeneracy information upon a return from thesleep mode and determines that there is degeneracy control, a returnfrom sleep mode is made in a state in which initialization processing ofthe printer engine is not allowed to be executed, without turning on thepower of the engine controller.

In the second embodiment, if degeneracy control is being executed whentransition to the power saving mode is made, upon return from the powersaving mode (sleep mode), return processing from the power saving modeis performed without activating the engine controller. Also, the secondembodiment is characterized in that if the degeneracy control iscancelled upon activation, normal activation processing is performed foractivating the engine controller.

Below, explanation will be given for power states in the power savingmode in the second embodiment.

(A) Sleep Mode

The sleep mode (power saving mode) is a state in which the electricpower consumption of the image forming apparatus 101 is reduced as muchas possible, as in the case of the first embodiment. Peripheral devicesof the CPU 211 are put into a general suspend state (such as ACPI-S3),only parts capable of detecting a job (the electric power supplylocations 226) are powered, and electric power consumption of the imageforming apparatus 101 on the whole is reduced dramatically.Specifically, the CPU 211 saves a state of the image forming apparatus101 to the DISK 216 or in backup RAM, turns off the switch 233, andstops the electric power supply to the main controller 210. Here the CPU211 itself stops operating, but when the electric power supply locations226 receive a job, an interrupt to the CPU 211 is caused to occur, andthe power of the main controller 210 is turned on. With this, the CPU211 reads out the state of the image forming apparatus 101 stored in theDISK 216 or the backup RAM, performs resetting, and transitions to astandby state, having returned to the state immediately before the powerof the main controller 210 was turned off. In the sleep mode, becausenot many hardware components can operate, the only function is totransition to the standby state. A job is received, after transitioningto the standby state.

(B) Standby State

This is a state in which the main controller 210 is being powered. Inthis state, operation by an operator is received from the operation unit220, and jobs, and the like, are received from the LAN I/F 221 via thenetwork 102. Because the electric power supply to the engine controller200 is turned off, the CPU 211 executes jobs after powering the enginecontroller 200 by turning on the switch 222. It is possible to reducestandby power consumption in the standby state by stopping electricpower supply to the engine controller 200 and the printer engine 240when the job completes by turning off the switch 222, and only poweringnecessary devices.

In the image forming apparatus 101 having the above configuration, forexample, an instruction to return from the sleep mode is input from theoperation unit 220, for example. With this, firstly, the main controller210 and the engine controller 200 execute start-up operations of suchkinds of initialization as initial setting of each of the CPUs andmemory checking.

Next, the engine controller 200 initiates control of the printer engine240 which is under its control. At this time, generally, statetransition information of the image forming apparatus 101 is detected bythe main controller 210, and based on the detected information, theengine controller 200 performs control on each driving target. The statetransition information is information indicating whether, for example,an activation is due to the power being turned on or due to returningfrom the sleep mode, and how to transition to the next state.

In contrast to this, in the image forming apparatus 101 according to thesecond embodiment, by the configuration of a function to be explainednext, the engine controller 200 initiates control of each driving targetunder its control without waiting for start-up operation of the maincontroller 210.

The software configuration of the main controller 210, the enginecontroller 200 and the software configuration of the image formingapparatus 101 according to the second embodiment are common to FIG. 3according to the previously described first embodiment, and soexplanation will be omitted.

In the image forming apparatus 101 according to the second embodiment,the engine controller 200 initiates control of the driving target (theprinter engine 240) without waiting for the start-up operation of themain controller 210 to end.

FIG. 6 is a flowchart for describing activation processing in the maincontroller 210 of the image forming apparatus 101 according to thesecond embodiment in a case where a power is activated. Note, processingillustrated by this flowchart is realized by the CPU 211 executing aprogram stored in the ROM 215.

Firstly, in step S601, the CPU 211 acquires a value (hereinafterreferred to as a degeneracy mode) saved in the DISK 216 indicatingwhether or not the engine controller 200 was performing degeneracycontrol. Here, in a case where the degeneracy mode is on, i.e. where thedegeneracy control was performed, the processing proceeds to step S602,and the presence or absence of the degeneracy return operation isdetermined. On the other hand, in a case where the degeneracy mode isoff, i.e. the engine controller 200 was not performing degeneracycontrol, the processing proceeds to step S603 because normal activationprocessing will be continued. In step S602, the CPU 211 determineswhether or not an operation for returning from the degeneracy control(degeneracy return operation) is performed. The degeneracy returnoperation is an operation such as an operation to return from an errorby, for example, a serviceman, or a part replacement performed when thepower of the image forming apparatus 101 is turned off in order toprocess an error that caused degeneracy control to be performed. Whetheror not this degeneracy return operation was performed is determinedbased on whether or not the main controller 210 was instructed that theserviceman that performed the operation to return from the error, forexample, performed a degeneracy return check via the operation unit 220upon the power activation of the image forming apparatus 101. In stepS602, when the CPU 211 determines that the degeneracy return operationwas performed, the processing proceeds to step S603; otherwise, becauseprocessing such as operation for return from error or part replacementis not finished, the processing proceeds to step S607 and activation isperformed in accordance with the degeneracy control.

In step S603, the CPU 211 initiates electric power supply to the enginecontroller 200 by turning on the switch 222, and activates the enginecontroller 200 and the printer engine 240. Next, the processing proceedsto step S604, and the CPU 211 activates the engine controller 200, andreceives a degeneracy detection result from the engine controller 200 byperforming initialization processing. When the engine controller 200executes initialization (calibration) of the printer engine 240, anddetects a problem in the printer engine 240, the engine controller 200determines whether or not the problem is one for which degeneracycontrol is possible. If degeneracy control can be performed, thedegeneracy mode is turned on, and saved to the DISK 216. Here, when noproblem in the printer engine 240 is detected, the degeneracy mode isturned off and saved to the DISK 216. Note, at this time, if the erroris such that repairs by a serviceman are necessary, configuration may betaken such that something to that effect is saved to the DISK 216, andactivation processing is not executed thereafter.

Next, the processing proceeds to step S605, and the CPU 211 determineswhether or not the degeneracy mode is on by reading out the value of thedegeneracy mode saved in the DISK 216. Here, when it is determined thatthe degeneracy mode is on, the processing proceeds to step S607, andwhen it is determined that the degeneracy mode is off, the processingproceeds to step S606. In step S606, because the printer engine 240 isin a state in which it is possible to activate normally, the CPU 211causes activation of the main controller 210 to complete by performingnormal activation, and the processing ends.

On the other hand, in step S607, the CPU 211 performs activation withthe degeneracy mode on, and the processing completes. In activation whenthe degeneracy mode is on, the CPU 211 leaves the switch 222 turned off,and electric power supply to the engine controller 200 stopped. Here,the CPU 211 cannot perform communication with the engine controller 200,but performs activation processing based on information of the enginecontroller 200 and the printer engine 240 saved to the DISK 216 upon theprevious activation.

By the above processing, activation processing can be changed inaccordance with whether an error occurred in the printer engine 240 anddegeneracy control is being performed, or whether the degeneracy controlis cancelled, upon activation of the main controller 210 due to thepower of the image forming apparatus 101 being turned on. In this way,even if the activation is due to the power of the image formingapparatus being turned on, it is determined whether or not thedegeneracy mode is on, and activation control of the printer engine canbe performed in accordance with the determination result.

FIG. 7 is a flowchart for describing activation processing in the enginecontroller 200 of the image forming apparatus 101 according to thesecond embodiment due to the power being turned on. Note, thisprocessing is realized by the CPU 201 executing a program stored in theROM 203.

Firstly, in step S701, the CPU 201 performs initialization processing ofthe hardware of the image forming apparatus 101 and the printer engine240. Here, the CPU 201 performs initialization processing of such thingsas a fixing heater and a fixing roller of the printer engine 240,various sensors and driving units. Next, the processing proceeds to stepS702, the CPU 201 determines the existence or absence of an errordetected in the initialization processing of step S701; if there is anerror, the processing proceeds to step S703, and if there is no error,the processing ends.

In step S703, the CPU 201 determines whether or not the error detectedin step S702 is a target of the degeneracy control. In a case where itis determined that the error is a target of degeneracy control, theprocessing proceeds to step S704; because in a case where the error isdetermined not to be a target of the degeneracy control the activationprocessing cannot continue, a serviceman call state is transitioned intoand the processing proceeds to step S706. In step S706, the CPU 201transitions the status of the engine controller 200 into the servicemancall state. Here, the serviceman call state is a state in which untilrepairs are performed by a serviceman, the functions of the imageforming apparatus 101 cannot be used. Next, the processing proceeds tostep S707, and the CPU 201 sends notification that the serviceman callstate has been entered, based on the error detected in step S702, anddisplays the error to the operation unit 220, and the processing ends.

On the other hand, in step S704, the CPU 201 transitions the status ofthe engine controller 200 into the degeneracy state. Next, theprocessing proceeds to step S705, and the CPU 201 sends notification tothe main controller 210 that the engine controller 200 and the printerengine 240 are transitioning to the degeneracy state, based on the errordetected in step S702, and the processing ends.

As explained above, the engine controller 200 initiates activationprocessing in accordance with an instruction of the main controller 210.When the printer engine error is detected upon activation due to thepower being turned on, in accordance with the content of the error,either the degeneracy state is transitioned into, or the serviceman callstate is transitioned into, and that result is sent in notification tothe main controller 210.

Also, degeneracy control activation, or the serviceman call status ornormal activation can be performed independently of whether the enginecontroller 200 instructed a return from the power saving mode state, orwhether power activation of the image forming apparatus 101 wasperformed.

FIG. 8 is a flowchart for describing processing in a case where the maincontroller 210 of the image forming apparatus 101 according to thesecond embodiment returns from the power saving mode. Note, thisprocessing is realized by the CPU 211 executing a program stored in theROM 215.

Firstly, in step S801, the CPU 211 determines the value (ON/OFF) of thedegeneracy mode saved in the DISK 216. Here, in a case where thedegeneracy mode is on, the processing proceeds to step S802, and in acase where the degeneracy mode is off, the processing proceeds to stepS803. In step S802, the CPU 211 performs return processing in the powersaving mode when in degeneracy. In the return processing in the powersaving mode when in degeneracy, the CPU 211 completes the returnprocessing from the power saving mode without turning on the switch 222and performing negotiation with the engine controller 200.

On the other hand, in step S803, the CPU 211 activates by turning on theswitch 222 and initiating powering of the engine controller 200. Withthis, the engine controller 200 executes error detection processingshown in FIG. 7 upon the engine controller activation, and performsprocessing in accordance with the detection result. Next, the processingproceeds to step S804, and the CPU 211 acquires results of calibrationof the engine controller 200 and the printer engine 240, and detectionresults of the various sensors, performs collaborative operation, andcompletes return processing from the power saving mode.

As explained above, by the image forming apparatus according to thesecond embodiment, it is determined whether or not the degeneracy modeis on (degeneracy control was being executed) upon activation, and in acase where the degeneracy mode is on, return processing can be performedwithout activating the engine controller 200.

Also, in a case where the degeneracy mode is on, it is determinedwhether or not operation to return from the error was performed, and itis possible that the engine controller 200 only be activated in a casewhere the return operation was performed. As a result, it is possible torestrict unnecessary calibration of the printer engine 240.

[Third Embodiment]

Next, explanation will be given for the third embodiment of the presentinvention. Note, because the hardware configuration of the image formingapparatus 101 according to the third embodiment is the same asconfiguration in FIG. 2 according to the previously described firstembodiment, its explanation will be omitted.

The software configuration of the main controller 210 and the enginecontroller 200 of the image forming apparatus 101 according to a thirdembodiment is common to FIG. 3 according to the previously describedfirst embodiment, and so explanation will be omitted.

The engine control section 311 of the engine controller 200 controls theengine controller 200 on the whole. The engine control section 311 givesinstructions to the engine activation control section 312, and acquiresinformation from the degeneracy detection section 313. In a case where ashutdown request is sent in notification from the main controller 210 tothe engine controller 200, the engine control section 311 makes aninstruction for finishing processing to each controller of the enginecontroller 200. The engine control section 311 makes a notification tothe main controller 210 of shutdown preparation completion whenfinishing processing of each controller completes. In a case where poweris activated for the engine controller 200 by control of the maincontroller 210, the engine control section 311 makes an instruction forinitialization to the engine activation control section 312. The engineactivation control section 312 receives this instruction, makes acalibration instruction to the printer engine 240, and makes aninitialization instruction to other controllers in the engine controller200. In this case, the engine activation control section 312 checks astatus of a physical signal line (hereinafter referred to as LIVEWAKEsignal line) between the main controller 210 and the engine controller200. In a case where the LIVEWAKE signal line is on, only initializationof the engine controller 200 is performed without performinginitialization of the printer engine 240; in a case where it is off,control is made so that the printer engine 240 and the engine controller200 are initialized. The degeneracy detection section 313 receivesinformation from the printer engine 240 that an error occurred due totrouble in a part, and sends in notification that information asdegeneracy information to the main controller 210.

FIG. 9 is a flowchart for describing processing in the main controller210 in a case where the image forming apparatus 101 according to a thirdembodiment transitions to the power saving mode. Note, this processingis realized by the CPU 211 executing a program stored in the ROM 215.

Firstly, in step S901, the CPU 211 determines whether or not degeneracyinformation is sent in notification from the engine controller 200, andif the degeneracy information is sent in notification, the processingproceeds to step S902, the degeneracy information is retained in a backup RAM or the DISK 216. Next, the processing proceeds to step S903, andthe CPU 211 determines whether or not a transition condition for theimage forming apparatus 101 to transition to the power saving mode issatisfied, and in a case where it is determined that the transitioncondition is satisfied, the processing proceeds to step S904. In stepS904, upon transition to the power saving mode, the degeneracyinformation stored in step S902 is acquired, and it is determinedwhether or not the degeneracy state is entered. Here, in a case where itis determined that the degeneracy state is entered, the processingproceeds to step S905, and the CPU 211 outputs an on signal to theLIVEWAKE signal line.

On the other hand, in step S904, in a case where it is determined thatthe degeneracy state is not entered, the processing proceeds to stepS906, and the CPU 211 outputs an off signal to the LIVEWAKE signal line.After executing either step S905 or step S906 in this way, theprocessing proceeds to step S907, and the CPU 211 transmits a shutdownrequest to the engine controller 200 via the external I/F 217. Next, theprocessing proceeds to step S908, the CPU 211 waits to be notified ofthe shutdown preparation completion by the engine controller 200, andwhen the shutdown preparation completion notification is received, theprocessing proceeds to step S909. In step S909, the CPU 211 stopselectric power supply to the engine controller 200 by turning off theswitch 222.

By the third embodiment, the main controller 210 stores degeneracyinformation from the engine controller 200. Next, upon transition intothe power saving mode, a signal for controlling initialization uponreturn of the printer engine 240 and the engine controller 200 isoutput.

FIG. 10 is a flowchart for describing shutdown processing by the enginecontroller 200 of the image forming apparatus 101 according to the thirdembodiment. Note, this processing is realized by the CPU 201 executing aprogram stored in the ROM 203.

Firstly, in step S1001, the CPU 201 determines whether or not theshutdown request is sent in notification from the main controller 210via the external I/F 205. When the shutdown request has be sent innotification, the processing proceeds to step S1002, and the CPU 201makes a request for finishing processing to each controller of theengine controller 200. Then in step S1003, when the finishing processingof all of the control units completes, the processing proceeds to stepS1004, and the CPU 201 makes a notification to the main controller 210that the shutdown preparation completed.

FIG. 11 is a flowchart for describing processing in a case where themain controller 210 of the image forming apparatus 101 according to thethird embodiment returns from the power saving mode. Note, thisprocessing is realized by the CPU 211 executing a program stored in theROM 215.

Firstly, in step S1101, the CPU 211 instructs initiation of theactivation processing upon receipt of a print job instruction from theoperation unit 220 and the LAN I/F 221. Next, the processing proceeds tostep S1102, and the CPU 201 activates the power of the engine controller200.

FIG. 12 is a flowchart for describing processing in a case where theengine controller 200 of the image forming apparatus 101 according tothe third embodiment returns from the power saving mode. Note, thisprocessing is realized by the CPU 201 executing a program stored in theROM 203.

This processing is initiated by the power of the engine controller 200being activated, and firstly, in step S1201, the CPU 201 checks whetherthe LIVEWAKE signal line is on or off. In a case where the LIVEWAKEsignal line is off, the processing proceeds to step S1203; in a casewhere the LIVEWAKE signal line is on, the processing proceeds to stepS1202. In step S1202, because the degeneracy state is entered, the CPU201 performs only initialization of the engine controller 200 withoutexecuting initialization processing of the printer engine 240, and theprocessing ends.

On the other hand, in step S1203, because the degeneracy state is notentered, the CPU 201 instructs initialization to each of the controllersof the engine controller 200 and to the printer engine 240. Next, theprocessing proceeds to step S1204, the CPU 201 determines whether or notan error occurred during the initialization of the printer engine 240,and when no error occurred, the processing ends. On the other hand, whenan error occurred, the processing proceeds to step S1205, and the CPU201 determines whether or not the error sent in notification is an errordue to one or more parts of the printer engine 240 being troubled, andwhether the error is one for which the degeneracy control is possible.In a case where it is determined that it is an error for which thedegeneracy control is possible, the processing proceeds to step S1206,and the CPU 201 sends in notification to the main controller 210 thatthe error for which degeneracy is possible occurred, and the degeneracyinformation. Then the processing proceeds to step S1207, and the CPU 201controls the printer engine 240 in degeneracy.

On the other hand, in a case where, in step S1205, the CPU 201determines that it is an error for which degeneracy control is notpossible, the processing proceeds to step S1208, and the CPU 201 sendsin notification to the main controller 210 serviceman call stateinformation. Next, the processing proceeds to step S1209, and the CPU201 notifies the user that the serviceman call state is entered. Theengine controller 200 performs control in the serviceman call state.Here, the serviceman call state is a state in which until repairs areperformed by a serviceman, the functions of the image forming apparatus101 cannot be used.

As explained above, by the third embodiment, in a case where thedegeneracy control was being performed by the printer engine before thetransition to the power saving mode, initialization of the printerengine (calibration) is not executed upon return from the power savingmode.

Also, by third embodiment, an existing LIVEWAKE sequence can beutilized, and also because LIVEWAKE is set before entering the powersaving mode, there is the advantage that upon return from the powersaving mode, no special processing by the main controller is necessary.

(Other Embodiments)

Aspects of the present invention can also be realized by a computer of asystem or apparatus (or devices such as a CPU or MPU) that reads out andexecutes a program recorded on a memory device to perform the functionsof the above-described embodiment(s), and by a method, the steps ofwhich are performed by a computer of a system or apparatus by, forexample, reading out and executing a program recorded on a memory deviceto perform the functions of the above-described embodiment(s). For thispurpose, the program is provided to the computer for example via anetwork or from a recording medium of various types serving as thememory device (for example, computer-readable medium).

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2012-281757, filed Dec. 25, 2012, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image forming apparatus comprising: a printingunit configured to print an image on a sheet; an engine control unitconfigured to control the printing unit to execute a preparationoperation of the printing unit; an error detection unit configured todetect an error of the printing unit; a function restriction unitconfigured to restrict a function based on the error detected by theerror detection unit; and a power control unit configured to shift, in astate in which the function is restricted by the function restrictionunit, the image forming apparatus from a standby state in which power issupplied to the engine control unit to a sleep state in which power isnot supplied to the engine control unit; wherein the engine control unitdoes not control the printing unit to execute the preparation operationof the printing unit when the power control unit returns the imageforming apparatus from the sleep state to the standby state in a statein which the function is restricted by the function restriction unit. 2.The image forming apparatus according to claim 1, wherein the powercontrol unit stops power to the engine control unit when the powercontrol unit shifts the image forming apparatus from the standby stateto the sleep state.
 3. The image forming apparatus according to claim 1,wherein the power control unit supplies power to the engine control unitwhen the power control unit returns the image forming apparatus from thesleep state to the standby state.
 4. The image forming apparatusaccording to claim 1, further comprising: a control unit configured tocontrol the image forming apparatus, wherein the engine control unitcontrols the printing unit in accordance with control of the controlunit.
 5. The image forming apparatus according to claim 1, wherein theengine control unit controls the printing unit to execute thepreparation operation of the printing unit when the power control unitreturns the image forming apparatus from the sleep state to the standbystate in a state in which the function is not restricted.
 6. The imageforming apparatus according to claim 1, further comprising a receivingunit configured to receive first information indicating that the imageforming apparatus has returned from the sleep state to the standbystate, wherein the engine control unit does not control the printingunit to execute the preparation operation of the printing unit when thereceiving unit receives the first information in a state in which thefunction is restricted by the function restriction unit.
 7. The imageforming apparatus according to claim 1, wherein the engine control unitcontrols the printing unit to execute the preparation operation of theprinting unit when the image forming apparatus is started.
 8. The imageforming apparatus according to claim 7, further comprising a receivingunit configured to receive second information indicating that the imageforming apparatus is started, wherein the engine control unit controlsthe printing unit to execute the preparation operation of the printingunit when the receiving unit receives the second information.
 9. Theimage forming apparatus according to claim 8, wherein the engine controlunit controls the printing unit to execute the preparation operation ofthe printing unit after the receiving unit receives the secondinformation.
 10. The image forming apparatus according to claim 1,further comprising a storage unit configured to store degeneracyinformation indicating that the function is restricted by the functionrestriction unit, wherein the engine control unit reads the degeneracyinformation stored by the storage unit when the power control unitreturns the image forming apparatus from the sleep state to the standbystate, and then the engine control unit does not control the printingunit to execute the preparation operation of the printing unit based onthe read information.
 11. The image forming apparatus according to claim10, wherein the degeneracy information is stored in a non-volatilememory.
 12. The image forming apparatus according to claim 10, whereinthe power control unit stops power supply to the non-volatile memorywhen the power control unit shifts the image forming apparatus from thestandby state to the sleep state.
 13. The image forming apparatusaccording to claim 1, wherein the preparation operation of the printingunit includes at least one of initialization of a fixing heater,initialization of a fixing roller, initialization of a sensor, andinitialization of a driving unit.
 14. The image forming apparatusaccording to claim 1, wherein the sleep state is an ACPI-S3 state. 15.The image forming apparatus according to claim 1, wherein the powercontrol unit supplies power to at least one of a network interface thatreceives a packet from an external device, a main memory, and anoperation unit that receives a user operation in the sleep state. 16.The image forming apparatus according to claim 15, wherein the powercontrol unit supplies power to at least one of a network interface thatreceives a packet from an external device, a main memory, and anoperation unit that receives a user operation in the sleep state. 17.The image forming apparatus according to claim 1, wherein the imageforming apparatus does not execute the function being restricted by thefunction restriction unit and executes an executable function differentfrom the function being restricted by the function restriction unit. 18.The image forming apparatus according to claim 15, wherein the imageforming apparatus does not execute the function being restricted andexecutes an executable function different from the function beingrestricted.
 19. An image forming apparatus comprising: a printer enginethat prints an image on a sheet; an engine controller that controls theprinter engine to execute a preparation operation of the printer engine;and a power control unit that shifts, in a state in which an error hasoccurred in the printer engine, the image forming apparatus from astandby state in which power is supplied to the engine controller to asleep state in which power is not supplied to the engine controller;wherein the engine controller does not control the printer engine toexecute the preparation operation of the printer engine when the powercontrol unit returns the image forming apparatus from the sleep state tothe standby state in a state in which the error has occurred in theprinter engine.
 20. The image forming apparatus according to claim 19,wherein the power control unit stops power supply to the enginecontroller when the power control unit shifts the image formingapparatus from the standby state to the sleep state.
 21. The imageforming apparatus according to claim 20, wherein the engine controllerreceives first information indicating that the image forming apparatushas returned from the sleep state to the standby state, wherein theengine controller does not control the printer engine to execute thepreparation operation of the printer engine when the engine controllerreceives the first information in a state in which the error hasoccurred in the printer engine.
 22. The image forming apparatusaccording to claim 19, wherein the power control unit supplies power tothe engine controller when the power control unit returns the imageforming apparatus from the sleep state to the standby state.
 23. Theimage forming apparatus according to claim 19, further comprising: acontrol unit configured to control the image forming apparatus, whereinthe engine controller controls the printer engine in accordance withcontrol of the control unit.
 24. The image forming apparatus accordingto claim 19, wherein the engine controller controls the printer engineto execute the preparation operation of the printer engine when thepower control unit supplies power to the engine controller in a state inwhich the error has not occurred in the printer engine.
 25. The imageforming apparatus according to claim 19, wherein the engine controllercontrols the printer engine to execute the preparation operation of theprinter engine when the image forming apparatus is started.
 26. Theimage forming apparatus according to claim 19, wherein the enginecontroller receives second information indicating that the image formingapparatus is started, wherein the engine controller controls the printerengine to execute the preparation operation of the printer engine whenthe engine controller receives the second information.
 27. The imageforming apparatus according to claim 26, wherein the engine controllercontrols the printer engine to execute the preparation operation of theprinter engine after the engine controller receives the firstinformation.
 28. The image forming apparatus according to claim 19,further comprising a storage unit configured to store degeneracyinformation indicating that the error has occurred in the printerengine, wherein the engine controller reads the degeneracy informationstored in the storage unit when the engine controller starts, and thenthe engine controller does not control the printer engine to execute thepreparation operation of the printer engine based on the readinformation.
 29. The image forming apparatus according to claim 28,wherein the storage unit is a non-volatile memory.
 30. The image formingapparatus according to claim 28, wherein the power control unit stopspower supply to the storage unit when the power control unit shifts theimage forming apparatus from the standby state to the sleep state. 31.The image forming apparatus according to claim 19, wherein thepreparation operation of the printer engine includes at least one ofinitialization of a fixing heater, initialization of a fixing roller,initialization of a sensor, and initialization of a driving unit. 32.The image forming apparatus according to claim 19, wherein the imageforming apparatus does not execute the function being restricted andexecutes an executable function different from the function beingrestricted.
 33. A method of controlling an image forming apparatuscomprising a printing unit configured to print an image on a sheet andan engine control unit configured to control operation of the printingunit, the method comprising: detecting an error of the printing unit;restricting a function based on the detected error; and shifting, in astate in which the function is restricted, the image forming apparatusfrom a standby state in which power is supplied to the engine controlunit to a sleep state in which power is not supplied to the enginecontrol unit; and controlling the printing unit to execute a preparationoperation of the printing unit, wherein the engine control unit does notcontrol the printing unit to execute the preparation operation when theimage forming apparatus is returned from the sleep state to the standbystate in a state in which the function is restricted.
 34. A method ofcontrolling an image forming apparatus comprising a printer engine thatprints an image on a sheet and an engine controller that controlsoperation of the printer engine, the method comprising: controlling toshift, in a state in which an error has occurred in the printer engine,the image forming apparatus from a standby state in which power issupplied to the engine controller to a sleep state in which power is notsupplied to the engine controller; and controlling the printing engineto execute a preparation operation of the printing engine, wherein theengine controller does not control the printer engine to execute thepreparation operation when the image forming apparatus is returned fromthe sleep state to the standby state in a state in which the error hasoccurred in the printer engine.